相关论文: On the B to D* tau nu Sensitivity to New Physics
In the Standard Model, scalar contributions to leptonic and semileptonic decays are helicity suppressed. The hypothesis of additional physical neutral/charged Higgses can enhance such scalar contributions and give detectable effects…
I review the current status of measurements involving semi-tauonic $B$ meson decay at the $B$-factories. I briefly discuss the experimental methods and highlight the importance of background contributions especially from poorly understood…
We revisit the status of the new-physics interpretations of the anomalies in semileptonic $B$ decays in light of the new data reported by Belle on the lepton-universality ratios $R_{D^{(*)}}$ using the semileptonic tag and on the…
The semileptonic decay channel B -> D tau nu is sensitive to the presence of a scalar current, such as that mediated by a charged-Higgs boson. Recently the BaBar experiment reported the first observation of the exclusive semileptonic decay…
Latest measurement of the ratio of branching ratios $R_D = \mathcal B(B \to D\,\tau\,\nu)/\mathcal B(B \to D\,l\,\nu)$ and $R_{D^{\ast}} = \mathcal B(B \to D^{\ast}\,\tau\,\nu)/\mathcal B(B \to D^{\ast}\,l\,\nu)$, where $l$ is either an…
We review possible impact of beyond Standard Model physics in the third generation leptonic and semileptonic B decays.
Decays of B mesons into final states containing a tau lepton are sensitive to new charged-current interactions that break lepton-flavor universality. These decays have been studied only at e+e- colliders, where the low-background…
Recently, several indications of lepton non-universality observables have been perceived in semileptonic $B$ meson decay processes, both in the neutral-current ($b \to s ll $) and charged-current ($b \to c l \bar \nu_l$) transitions.…
The latest BaBar measurements of the ratios ${\cal R}(D^{(*)})=\displaystyle{\frac{{\cal B}(B \to D^{(*)} \tau {\bar \nu}_\tau)}{{\cal B}(B \to D^{(*)} \mu {\bar \nu}_\mu)}}$ deviate from the Standard Model predictions at the global level…
Discrepancies have been noted between experimental measurements and Standard Model predictions for various observables related to the $B\to(K, K^*,\phi) ll$ processes. Recently, the Belle-II Collaboration observed a $2.8\sigma$ deviation…
Recent experimental results on exclusive semi-tauonic B meson decays, B -> D(*) tau nu, showing sizable deviations from the standard model prediction, suggest a new physics in which the structure of the relevant weak charged interaction may…
In recent times, the charged-current mediated semileptonic $b \to c \tau \bar \nu_\tau$ processes have attracted a lot of attention after the observation of lepton non-universality ratios, $R_{D^{(*)}}$, $R_{J/\psi}$ and the measurements on…
Decays of B mesons to states involving tau leptons can be used as a tool to search for the effects of new physics, such as those involving a charged Higgs boson. The experimental status of the decays B -> tau nu and B -> D^(*) tau nu is…
The BaBar Collaboration has recently reported the measurement of the ratio of the branching fractions of $\bar{B} \to D(D^{*}) \tau^{-} \bar{\nu_\tau}$ to $\bar{B} \to D(D^{*}) \ell^{-} \bar{\nu_\ell}$ which deviates from the Standard Model…
We review the current status and implications of the anomalies (i.e. deviations from the Standard Model predictions) in semi-leptonic $B$ meson decays, both in the charged and in the neutral current. In $b\to s\ell^+\ell^-$ transitions…
Deviations from the standard model prediction have been observed not only in $b \to c$ charged current interactions but also in $b \to s$ flavor changing neutral current interactions. In particular, the deviation observed in the measured…
We examine in detail the semi-leptonic decay $\Lambda_b \to \Lambda_c \tau{\bar \nu}_{\tau}$, which may confirm previous hints, from the analogous $B$ decay, of a new physics beyond the standard model. First of all, starting from rather…
Semileptonic and purely leptonic decays of B meson to $\tau$, such as $B\to D^{(\ast)}\tau\nu_{\tau}$ and $B\to\tau\nu_\tau$ are studied. Recognizing that there already were some weak hints of possible deviations from the SM in the…
Recent experimental results on angular observables in the rare decay $B\to K^*\mu^+\mu^-$ show significant deviations from Standard Model predictions. We investigate the possibility that these deviations are due to new physics. Combining…
The BaBar measurements of the ratios ${\cal R}(D^{(*)})=\frac{{\cal B}(B \to D^{(*)} \tau {\bar \nu}_\tau)}{{\cal B}(B \to D^{(*)} \mu {\bar \nu}_\mu)}$ deviate from the standard model expectation, while new results on the purely leptonic…